نتایج جستجو برای: clinical dosimetry
تعداد نتایج: 1168967 فیلتر نتایج به سال:
Dosimetry of eye plaques for ocular tumors presents unique challenges in brachytherapy. The challenges in accurate dosimetry are in part related to the steep dose gradient in the tumor and critical structures that are within millimeters of radioactive sources. In most clinical applications, calculations of dose distributions around eye plaques assume a homogenous water medium and full scatter c...
PURPOSE VMAT involves multi-parameter modulations, thus presenting multi-dimensional challenges. Here, we present a viable approach to VMAT patient specific QA using EPID-based dosimetry for spine VMAT SRS casesMethods: Our spine VMAT SRS plans consisted of two full arcs and were optimized with 6 MV photons for a Varian Trilogy LINAC. The QA plans were computed by resetting all control points t...
The solid state active detectors, widely used for conventional radiotherapy, such as diamond detectors (DD) and diodes may be attractive tools also in dosimetry of therapeutic proton beams. Diodes are broadly applied in oncology clinics and routinely used for in-vivo dosimetry [1, 8]. These real-time detectors are rugged, relatively inexpensive and provide on-line readings, what allows for quic...
Electronic portal imaging devices (EPIDs) have been the preferred tools for verification of patient positioning for radiotherapy in recent decades. Since EPID images contain dose information, many groups have investigated their use for radiotherapy dose measurement. With the introduction of the amorphous-silicon EPIDs, the interest in EPID dosimetry has been accelerated because of the favourabl...
This study compares the EPID dosimetry algorithms of two commercial systems for pretreatment QA, and analyzes dosimetric measurements made with each system alongside the results obtained with a standard diode array. 126 IMRT fields are examined with both EPID dosimetry systems (EPIDose by Sun Nuclear Corporation, Melbourne FL, and Portal Dosimetry by Varian Medical Systems, Palo Alto CA) and th...
PRESAGE is a radiochromic solid dosimeter which shows promising potential for 3D proton beam dosimetry. Since an idea dosimeter should be water-equivalent, total depth dose distributions in two PRESAGE formulations irradiated by a 62 MeV proton beam were compared with that in water using GEANT4 Monte Carlo simulations. The dose delivered by secondary particles was also calculated. Our results s...
Since the introduction of volumetric chemical dosimetry with Fricke gel dosimeters in the 1980s, three-dimensional (3D) dosimetry has been a promising technique for the clinic, since it provides a unique methodology for 3D dose measurement of the complex conformal dose distributions achieved by modern techniques such as Intensity Modulated and Volumetric Arc Radiation Therapy. In the last decad...
background: absolute dosimetry of external beam radiotherapy is carried out by the use of ionization chambers. these chambers must be calibrated at a standard dosimetry laboratory before any use in clinical dosimetry. the secondary standard dosimetry laboratory of iran (ssdl) has the duty of calibrating the ionization chambers used in radiotherapy centers in iran. materials and methods: the pre...
A heterogeneous distribution of radionuclides emitting low-energy electrons in the testicles may result in a significant difference between an absorbed dose to the radiosensitive spermatogonia and the mean absorbed dose to the whole testis. This study focused on absorbed dose distribution in patients at a finer scale than normally available in clinical dosimetry, which was accomplished by combi...
Occupational radiation doses from interventional procedures have the potential to be relatively high. The requirement optimise these encourages use of electronic or active personal dosimeters (APDs) which are now increasingly used in hospitals. They typically tandem with a routine passive dosimetry monitoring programme, APDs for real-time readings, training purposes and when new imaging technol...
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